1. Field of the Invention
The invention is related to a mobile communication apparatus capable of improving power saving effects as to either a display unit or a backlight of the display unit.
2. Description of the Related Art
In conventional mobile communication apparatuses such as portable telephones and Personal Digital Assistants (PDAs), hinge portions are provided on main bodies to make main bodies openable and closable. More specifically, the mobile communication apparatus is divided into display-sided casings where optical sensors is mounted and main body keyboard-sided casings by employing the hinge portions. Then, for example, an open/close detecting apparatus is installed in a control circuit in the main body keyboard-sided casing. When the two overlapped casings are opened, for instance, a keyboard and a display are exposed on the inner side of these two casings.
Among these conventional mobile communication apparatuses, some mobile communication apparatuses perform the below-mentioned control operations: That is, when two sets of casings are opened, brightness around an optical sensor is determined by the optical sensor built in one casing. When the surrounding is bright, the mobile communication apparatus performs a control to turn off backlight of display units. When the surrounding is dark, the mobile communication apparatus performs a control to turn on the backlight. Furthermore, there are some mobile communication apparatuses which perform the following control operations: That is, after the backlight illuminating display units is turned ON, when telephone calls are not made and key inputs are not entered within a certain time duration, the mobile communication apparatus performs a control to turn off the backlight. When key inputs are entered after the turn-OFF operation, the mobile communication apparatus performs a control to turn on the backlight again (see JP-A-2002-57776, for instance).